6 MISCELLANEOUS PUBLICATION 1348, U.S. DEPARTMENT OF AGRICULTURE 
adults contained a patchwork of tall and short 
cover, whereas young nymphs survived in high 
numbers on low vegetation providing green feed 
was plentiful. In general, he found that dense or tall 
vegetation is not readily warmed by the sun, nor so 
readily cooled by the free circulation of air as is thin 
vegetation. Consequently, dense vegetation is de- 
sirable for shelter, whereas thin vegetation pro- 
vides better conditions for diurnal activity in favor- 
able weather. 
Anderson (1964) found grasshopper populations 
to be inversely proportional to the plant height and 
amount of shading. Plains areas were found to be 
occupied more frequently and in larger numbers 
when foliage cover was below 40 percent. In Ari- 
zona, Nerney (1960) found that as the length of the 
grass blades increased, perennial grass cover in- 
creased, total vegetation cover tended to increase, 
the grasshopper population decreased, and the per- 
centage of damage to the perennial grass decidedly 
decreased. Dempster (1955), in Britain, investigat- 
ing factors causing small-scale movement of Chor- 
thippus parallelus and C. brunneus Thunb., found 
that nymphs and adult males tended to move from 
short into long vegetation, whereas females of C. 
parallelus showed a reverse tendency. 
Bailey and Riegert (1971) thought that the food 
preferences of Encoptolophus sordidus costalis in 
Canada were related to the behavioral characteris- 
tics of the grasshoppers in their particular habitat. 
They observed this species to be a soil surface 
dwelling grasshopper. Since a preferred food plant 
such as Carex eleocharis Bailey is low growing, 
they suggest that the sedge is preferred because of 
the intimate association. 
Ueckert et al. (1972) studied the influence of 
plant frequency upon the feeding habits and diets of 
14 grasshopper species in Colorado. They found sta- 
tistically significant correlations between the fre- 
quency of plants in the habitat and the frequency of 
plants in the grasshopper diets. They concluded 
that the diets of grasshoppers are influenced by 
the plant composition in the habitat, even though 
strong feeding preferences are expressed. 
The diets of species that feed on a few plant spe- 
cies are generally influenced more by plant fre- 
quency than are diets of species that feed on many 
different plant species. According to some authors, 
the grouping or distribution of grasshoppers de- 
pends upon the type of soil. Isely (1938) noted that 
soil structure and texture play a part in grasshop- 
per distribution and delimiting egg-laying sites. 
Anderson (1966) indicated that Aulocara elliotti has 
a preference for undisturbed soil (as versus sifted 
soil) and found that egg pods were usually attached 
to solid objects such as small pebbles or roots. 
Grazing Influence 
A number of workers have recognized that de- 
pleted and overgrazed range is a favorite habitat 
for grasshoppers (Waldron 1898; Swenk 1913; Tre- 
herne and Buckell 1924; Ball 1936, 1937; Parker 
1937, 1952; Dibble 1940; Mills 1941; Clark 1948; 
Nerney 1958; and Nerney and Hamilton 1969. Both 
Dibble (1940) and Parker (1952) stated that over- 
grazing by grasshoppers can be conducive to soil 
erosion, particularly when drought and mismanage- 
ment of the land also occur. Some quantitative re- 
sults have been obtained regarding grazing pres- 
sure and grasshopper numbers. 
In 1921, Buckell (1936) started an experiment to 
show the effect of overgrazing on the oviposition 
sites of Camnula pellucida. He fenced a 2-ha area 
that was normally used as an oviposition site by C. 
pellucida, and excluded all livestock. In 1921, when 
the grasshoppers returned to the egg beds for ovi- 
position, they selected the closely grazed area out- 
side of the fenced areas for oviposition. Buckell 
reported no eggs were laid in the 2-ha area for sev- 
eral years following the fencing. In Oklahoma, 
Coyner (1939) compared two overgrazed areas with 
a moderately grazed area. He collected 444 adult 
grasshoppers on the overgrazed areas and com- 
pared them with 63 on the moderately grazed area. 
Weese (1939) also made a similar comparison ex- 
cept all orders of insects were included in his study. 
He found that the most abundant insects in the 
overgrazed area were the grasshoppers of the sub- 
family Cyrtacanthacridinae. The total insect popu- 
lation in the overgrazed grassland is, on the aver- 
age, approximately four times as great as in the 
normal prairie. An important factor in the distribu- 
tion of grasshoppers and perhaps other insects is 
the presence of younger and more tender plants in 
the area in which the vegetation is kept down by - 
the combination of livestock grazing and insect 
pressure. The relative number of insects collected 
by sweeping in the two types of habitat follows: 
Order Overgrazed area Normal area 
Coleoptera 23 10 
Diptera 6 6 
Hemiptera 12 2 
Homoptera 43 10 
Hymenoptera 28 6 
Orthoptera 36 4 
